In recent years, thin, light, and low-power-consumption display devices such as liquid crystal display devices have been widely used. It is noteworthy that such display devices have been mounted, for example, on electronic book devices, smartphones, mobile phones, tablet devices, PDAs (portable information devices), laptop personal computers, portable gaming devices, car navigation devices, and the like. It is expected that in the future, development and prevalence of electronic paper, which is an even thinner display device, will be rapidly advanced. Under such circumstances, it is now a common challenge to reduce power consumption of display devices and to improve display quality of the display devices.
Therefore, conventionally, there have been various proposed technologies intended to overcome the challenge of the display devices.
For example, there is a technology used that increases a refresh rate in order to improve display quality. For example, the refresh rate is increased from 60 Hz (i.e. 60 fps) to 120 Hz (i.e. 120 fps) while a video image is being displayed. This allows a smoother motion to be delivered and a reduction in the occurrence of a display malfunction such as flickering.
However, since the number of times a display panel is driven increases along with the increase in the refresh rate, electric power consumption also becomes increased. Therefore, the use is made of a technology that, on the contrary, reduces a refresh rate in a case where emphasis is placed on a reduction in electric power consumption.
As a specific example, Patent Literature 1 discloses a technology in which (i) image quality is improved by actively increasing a refresh rate in a case where false contours are likely to occur or false contours are noticeable on a displayed image and (ii) power consumption is reduced by actively lowering the refresh rate in a case where false contours are unlikely to occur or false contours are unnoticeable on a displayed image.